In manufacturing, for example, semiconductor parts or flat panel displays, a substrate liquid processing apparatus has conventionally been used for performing various processings such as, for example, cleaning and etching, on substrates such as, for example, semiconductor wafers or liquid crystal substrates.
In the substrate liquid processing apparatus, a liquid processing is performed on a substrate using a processing liquid such as, for example, a cleaning liquid or an etching liquid. As for the processing liquid, for example, a liquid produced by mixing multiple kinds of chemical liquids at a predetermined mixing ratio (concentration), such as, for example, a standard clean-1 (SC-1) liquid (a mixed liquid of hydrogen peroxide, ammonium hydroxide, and pure water), is frequently used.
In a conventional substrate liquid processing apparatus, the respective chemical liquids are supplied at once to a tank at a predetermined mixing ratio in order to produce a processing liquid at a predetermined concentration. Then, in order to remove particles contained in the processing liquid, the processing liquid is circulated for a predetermined length of time or longer using a circulation flow line provided in the tank so that the processing liquid is purified by a filter provided in the circulation flow line. Then, the liquid processing of the substrate is performed using the processing liquid (see, e.g., Japanese Patent Laid-Open Publication No. 2009-172459).